/*
 * Copyright (C) 2008 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect.testing.testers;

import static com.google.common.collect.testing.features.CollectionFeature.ALLOWS_NULL_VALUES;
import static com.google.common.collect.testing.features.CollectionSize.ZERO;
import static com.google.common.collect.testing.features.ListFeature.SUPPORTS_SET;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.testing.Helpers;
import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.CollectionSize;
import com.google.common.collect.testing.features.ListFeature;

import java.lang.reflect.Method;

import org.junit.Ignore;

/**
 * A generic JUnit test which tests {@code set()} operations on a list. Can't be invoked directly;
 * please see {@link com.google.common.collect.testing.ListTestSuiteBuilder}.
 *
 * @author George van den Driessche
 */
@GwtCompatible(emulated = true)
@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
public class ListSetTester<E> extends AbstractListTester<E>
{
    @ListFeature.Require(SUPPORTS_SET)
    @CollectionSize.Require(absent = ZERO)
    public void testSet()
    {
        doTestSet(e3());
    }

    @CollectionSize.Require(absent = ZERO)
    @CollectionFeature.Require(ALLOWS_NULL_VALUES)
    @ListFeature.Require(SUPPORTS_SET)
    public void testSet_null()
    {
        doTestSet(null);
    }

    @CollectionSize.Require(absent = ZERO)
    @CollectionFeature.Require(ALLOWS_NULL_VALUES)
    @ListFeature.Require(SUPPORTS_SET)
    public void testSet_replacingNull()
    {
        E[] elements = createSamplesArray();
        int i = aValidIndex();
        elements[i] = null;
        collection = getSubjectGenerator().create(elements);

        doTestSet(e3());
    }

    private void doTestSet(E newValue)
    {
        int index = aValidIndex();
        E initialValue = getList().get(index);
        assertEquals(
                "set(i, x) should return the old element at position i.",
                initialValue,
                getList().set(index, newValue));
        assertEquals("After set(i, x), get(i) should return x", newValue, getList().get(index));
        assertEquals("set() should not change the size of a list.", getNumElements(), getList().size());
    }

    @ListFeature.Require(SUPPORTS_SET)
    public void testSet_indexTooLow()
    {
        try
        {
            getList().set(-1, e3());
            fail("set(-1) should throw IndexOutOfBoundsException");
        }
        catch (IndexOutOfBoundsException expected)
        {
        }
        expectUnchanged();
    }

    @ListFeature.Require(SUPPORTS_SET)
    public void testSet_indexTooHigh()
    {
        int index = getNumElements();
        try
        {
            getList().set(index, e3());
            fail("set(size) should throw IndexOutOfBoundsException");
        }
        catch (IndexOutOfBoundsException expected)
        {
        }
        expectUnchanged();
    }

    @CollectionSize.Require(absent = ZERO)
    @ListFeature.Require(absent = SUPPORTS_SET)
    public void testSet_unsupported()
    {
        try
        {
            getList().set(aValidIndex(), e3());
            fail("set() should throw UnsupportedOperationException");
        }
        catch (UnsupportedOperationException expected)
        {
        }
        expectUnchanged();
    }

    @CollectionSize.Require(ZERO)
    @ListFeature.Require(absent = SUPPORTS_SET)
    public void testSet_unsupportedByEmptyList()
    {
        try
        {
            getList().set(0, e3());
            fail("set() should throw UnsupportedOperationException or IndexOutOfBoundsException");
        }
        catch (UnsupportedOperationException | IndexOutOfBoundsException tolerated)
        {
        }
        expectUnchanged();
    }

    @CollectionSize.Require(absent = ZERO)
    @ListFeature.Require(SUPPORTS_SET)
    @CollectionFeature.Require(absent = ALLOWS_NULL_VALUES)
    public void testSet_nullUnsupported()
    {
        try
        {
            getList().set(aValidIndex(), null);
            fail("set(null) should throw NullPointerException");
        }
        catch (NullPointerException expected)
        {
        }
        expectUnchanged();
    }

    private int aValidIndex()
    {
        return getList().size() / 2;
    }

    /**
     * Returns the {@link java.lang.reflect.Method} instance for {@link #testSet_null()} so that tests
     * of {@link java.util.Collections#checkedCollection(java.util.Collection, Class)} can suppress it
     * with {@code FeatureSpecificTestSuiteBuilder.suppressing()} until <a
     * href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6409434">Sun bug 6409434</a> is fixed.
     * It's unclear whether nulls were to be permitted or forbidden, but presumably the eventual fix
     * will be to permit them, as it seems more likely that code would depend on that behavior than on
     * the other. Thus, we say the bug is in set(), which fails to support null.
     */
    @GwtIncompatible // reflection
    public static Method getSetNullSupportedMethod()
    {
        return Helpers.getMethod(ListSetTester.class, "testSet_null");
    }
}
